A Transylvania University student wearing a red bandanna thought it was a joke when three men told him he was in the wrong territory and threatened to shoot him Sunday night, police said.

The student was playing Humans vs. Zombies, an organized version of playground tag popular on college campuses. Players wear bandannas to signify which team they are on — humans or zombies — and zombies are often in danger of being blasted with foam darts.

But bandannas in certain colors have been used to signify gang affiliations. The Bloods, one of the nation's most well-known gangs, and groups inspired by it identify with the color red.

Lexington Police spokeswoman Sherelle Roberts said the Transylvania student did not remember what gang the men mentioned.

Lexington police have acknowledged gangs are active in Lexington, although most aren't as organized as those in larger cities.

The incident happened about 10:15 p.m. Sunday as the student was walking along Fourth Street near Transylvania's campus. The three men pulled alongside him in a sport-utility vehicle "and advised him to remove his bandanna or they would shoot him," a police report said.

The student initially shrugged off the warning, but the men kept watching him as he walked away, Roberts said. The student took off the bandanna and reported the encounter to campus authorities, who referred it to Lexington police.

Investigators are trying to figure out whether it was a joke or a legitimate, gang-related threat.

"It's hard to verify if this was a prank or something more serious," Roberts said.

A campus alert was sent to students Sunday night, and players were asked to take off their bandannas. The Transylvania Gaming Society, a student organization, agreed Monday to cancel the game early and think of new ways to identify players the next time, said Bob Brown, associate dean of student affairs.

He said a security camera captured the interaction, but the video was grainy, and it was hard to make out details of the vehicle or the men inside.

The game began Friday and was scheduled to end Tuesday. Brown said 20 or fewer Transylvania students had participated.

"The students who do play it are really passionate about it," he said.

Humans vs. Zombies began in 2005 on the campus of Goucher College in Maryland. The idea spread through social media, and the game is now played by more than 700 registered groups, said Max Temkin, a co-founder of the game, which has a national organization.

College students play it to relieve stress, learn teamwork and act out fantasies of surviving during a zombie apocalypse — a concept made popular by horror movies and, more recently, The Walking Dead comics, created by Kentuckian Robert Kirkman, and the hit AMC TV show that it spawned.

Players on the zombie team typically seek out and tag "human" players, who defend themselves with foam weapons, such as NERF blasters and pool noodles, or by throwing marshmallows or rolled-up socks.

Zombies who are hit may not chase or tag humans for a short time. Humans who are tagged become members of the zombie team.

According to the rules on the game's official Web site, Humansvszombies.org, a zombie is designated by wearing a bandanna on his or her head. Members of the human team wear headbands or bandannas around their arms or legs.

Student organizations that register with the national group are given guidelines that suggest players wear neutral colors or "blaze-orange" bandannas, similar to the color worn by hunters or traffic officers.

"That's a color that we've researched that is highly visible and free of any political affiliation or gang affiliation or anything like that," Temkin said.

The organization sells an official orange bandanna, but groups are free to supply their own equipment and tweak rules to comply with campus regulations.

In the future, Brown said, Transylvania players will be asked to identify themselves with neon or bright colors "that couldn't be construed as anything else."

Temkin said this was the first time he had heard of such an incident. He said the usual reports of the game's "ill effects," such as injuries or fights, are mistakes — overreactions from onlookers who might be confused when they see a group of people chasing others.

"This is a pretty shocking and unique thing. We've never heard of anything like this happening," he said.